Aluminum housing for an electrical device

Abstract

An aluminum housing for an electrical device with an outer housing wall and at least a first and a second housing chamber that are electromagnetically shielded from each other, wherein the shielding is provided by at least one inner housing wall of the housing and at least one shielding plate which is in electrical contact with the housing walls of the housing in its peripheral area, is characterized according to the invention in that the shielding plate is made of aluminum, and that the electrical contact with the housing walls of the housing is provided at least sectionally by at least one spring element of the shielding plate which rests against a housing wall under spring preload.

Description

The invention relates to an aluminum housing for an electrical device having an outer housing wall and at least one first and one second housing chamber which are electromagnetically shielded from one another, wherein the shielding is effected by at least one inner housing wall of the housing and at least one shielding plate which is in circumferential electrical contact with housing walls of the housing in its edge region.In electrical or electronic devices having two regions shielded from one another electromagnetically, it is known to realize the shielding by means of a metallic shielding plate arranged in a metallic housing, for example in a die casting housing. The shielding plate separates, in the interior of the housing, a first region arranged on one side of the shielding plate from a second region arranged on an opposite side of the shielding plate. For this purpose, the shielding plate is usually firmly connected in its edge region in a circumferential manner to inner sides of the outer walls of the housing and / or to inner walls of the housing in an electrically contacting manner, for example by screw connections.An electrical device with such an aluminum housing is known from German laid-open specification DE 10 2018 114 309 A1. A metallic shielding plate is attached here in such a way that it overlaps a step-like projection of a housing wall in a planar manner in its edge region and is screwed to the latter. The screw connection forms here a two-dimensionally configured electrical contact between the shielding plate and the housing wall with a high surface pressure.The aluminum housing designed according to the invention has the advantage over the prior art of requiring less installation space and being easier to mount.This is achieved according to the invention in that the shielding plate consists of aluminum, and in that the electrical contact with housing walls of the housing is effected at least in sections by at least one spring element of the shielding plate which bears against a housing wall under spring prestress.The at least one spring element of the shielding plate is preferably formed integrally with the shielding plate.The at least one spring element of the shielding plate and the housing outer wall of the housing also preferably have punctiform or linear contact regions which are formed by spherical or cylindrical elevations.An exemplary embodiment of the invention is explained below with reference to the drawings. The figures show FIG. 1 shows a representation of an aluminum housing designed according to the invention in a plan view and in longitudinal section FIG. 2 shows an illustration of a punctiform and a linear contact region between a spring element of the shielding plate and the aluminum housing FIG. 3 shows a representation of an aluminum housing according to the prior art in a plan view and in longitudinal sectionThe aluminum housing according to the prior art shown in FIG. 3 has a first housing chamber 2 and a second housing chamber 3, which are electromagnetically shielded from one another. This shielding is effected on the one hand by an inner housing wall 4 of the housing and on the other hand by a metallic shielding plate 5. the shielding plate 5 is screwed in its edge region to housing walls 1, 4. The screwing to the housing inner wall 4, which, as can be seen in the longitudinal illustration, has a lower height than the housing outer wall 1, takes place on the upper side thereof. On the outer housing wall 1, in the region to which the shielding plate 5 has to be fastened, there is a step-shaped shoulder which has the same height as the inner housing wall 4 and on the upper side of which the shielding plate 5 is screwed in the same way. According to the current state of the art, such shielding plates are predominantly made of stainless steel and copper beryllium.In the aluminum housing according to the invention shown in FIG. 1, the two housing chambers 2, 3 are likewise electromagnetically shielded from one another by a housing inner wall 4 of the housing and by a metallic shielding plate 5. The shielding plate 5 is also screwed to the upper side of the housing inner wall 4 in sections of its edge region. In the region of the housing outer wall 1, however, the electrical contacting takes place by spring elements 6 of the shielding plate 5. these spring elements 6 are formed integrally with the shielding plate 5 and bear under spring prestress against the housing outer wall 1.According to the invention, the shielding plate 5 is made of aluminum. Aluminum not only has good EMC damping properties, but also brings about a weight advantage due to the low density compared to copper or stainless steel. A further advantage is that the electrical contact to the aluminum housing is resistant to bimetallic corrosion. In addition, aluminum has a lower shear modulus compared to steel and copper. The low spring rate as a result makes spring elements 6 made of aluminum less susceptible to component and process tolerances.The spring elements 6 of the shielding plate 5 and the housing outer wall 1 of the housing preferably have punctiform or linear contact regions which, on the one hand, reduce gaps and, on the other hand, are characterized by a high surface pressure (Hertzian surface pressure) in the contact region. In FIG. 2, the upper illustration shows punctiform contact regions which are formed by spherical elevations 6' of the spring element 6. In the lower illustration of FIG. 2, a linear contact region can be seen which is formed by a cylindrical elevation 6'' of the spring element 6. The direction of the spring force is represented by arrows labeled "F". The spherical or cylindrical elevations 6', 6" for forming the punctiform or linear contact regions do not necessarily have to be formed on the spring element 6, but can alternatively also be formed at corresponding points on the housing outer wall 1 of the housing.Due to the high surface pressure, the natural oxidation layers of the aluminum can be locally broken through. This results in a very low contact resistance. A time-consuming and thus cost-intensive coating can be dispensed with in this embodiment of the electrical contact.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2018 114 309 A1

[0003]

Claims

Aluminium housing for an electrical device, having an outer housing wall (1) and at least one first and one second housing chamber (2, 3) which are electromagnetically shielded from one another, wherein the shielding is effected by at least one inner housing wall (4) of the housing and at least one shielding plate (5) which is in circumferential electrical contact with housing walls (1, 4) of the housing in its edge region, characterized in that the shielding plate (5) consists of aluminium, and in that the electrical contact with housing walls (1, 4) of the housing is effected at least in sections by at least one spring element (6) of the shielding plate (5) which bears against a housing wall (1, 4) under spring prestress.Aluminium housing according to claim 1, characterised in that the at least one spring element (6) of the screening plate (5) bears under spring prestress against an outer housing wall (1) of the housing.Aluminium housing according to claim 1 or 2, characterised in that the at least one spring element (6) of the screening plate (5) is formed integrally with the screening plate (5).Aluminium housing according to one of claims 1 to 3, characterised in that the at least one spring element (6) of the screening plate (5) and the housing wall (1, 4) of the housing have punctiform contact regions which are formed by spherical elevations (6').Aluminium housing according to one of claims 1 to 3, characterised in that the at least one spring element (6) of the screening plate (5) and the housing wall (1, 4) of the housing have at least one linear contact region which is formed by a cylindrical elevation (6").

Images